Spark plug



G. HADRICH SPARK PLUG Filed July 21 1921 3mm Geoaee HADIacH.

Manage Patented Apr. 26, 1927.

UNITED STATES GEORGE HADRICH, OF DETROIT, MICHIGANI,

SPARK PLUG.

Application filed July 21,

This invention relates to spark plugs, and the primary obj ect of my invention is to furnish a spark plug with novel electrodes which will insure a multiplicity 0t sparks and consequently a positive tiring of an explosive mixture inthe cylinder of an internal combustion engine provided with the spark plug. The electrodes may be of va rious forms, all of which may be adjusted to provide a desired spark gap, and the configuration of the electrodes, relative to the spark plug body, is such as to reduce to a minimum the accumulation of carbon, grease and foreign matter on the electrode or spark plug body.

Another object of this invention is to furnish a spark plug with an auxiliary spark gap or resistance which will intensity and strengthen the action of a magneto included in the ignition system of an automobile, motor boat, or other craft having the power plant equipped with spark plugs in accordance with this invention.

The above and other objects are attained by constructions that will be hereinafter described and then clain'ied, and reference will now be had to the drawing, wherein Figure l is an enlarged vertical sectional view of a spark plug embodying features of my invention;

Fig. 2 is a similar view of a portion of the spark plug showing a modified form of electrode;

Figs. 3 and a are plan views of other forms of electrodes, and

Fig. 5 is a vertical sectional view of a one-piece electrode.

In the drawing the reference numeral 1 denotes a spark plug body having a threaded portion 2 and a nut portion 3, the nut portion 3 facilitating mounting of the threaded portion 2 in a cylinder block, so that the inner end of the spark plug body will communicate with or extend into the end of a cylinder.

The body 1 has a longitudinal bore 1 communicating with an inverted trusto conical shaped nose 5 of the body and the end of the nose 5 is serrated or notched to provide a series of circumierentially disposed teeth or spark points 6.

The outer or upper end of the bore 4: is enlarged to provide an annular seat 7 and the walls of the bore are screw-threaded, as at 8, to receive a gland or nut 9.

Seated in the spark plug body is a double 1921. Serial No. 486,319.

conical shaped insulator 10 made of porce lain or other insulating material, and the insulator has an annular collar 11 providing shoulders 12 confronting the seat 7 and the inner end'oi the gland or nut 9. Compressible cushion rings or washers 13 of a conventional form are interposed between the shoulders 12 of the insulator and the body 1 and the gland 9. i

The inner end or nose 1 1: of the insulator 1O protrudes into the nose 5 of the spark plug body 1 and the nose 14; cooperates with the body 1 in providing a chamber 15 which may receive carbon, oil or foreign matter should the same be forced into the spark plug body. In providing this space beyond the teeth or spark points 6 it will be impossible for carbon and other foreign matter to lodge on the teeth.

Axially oi the insulator 10 is an electrode rod 16 which has its inner end extending into a recess 17 in the nose 1d of the insulator. Detachably connected to the inner end of the rod 16 is the stem 18 of a semispherical or button shaped electrode 19 having a slot 20 to receive a screw driver or similar tool that may be conveniently used for attaching the electrode to the rod 16. The marginal edges of the electrode 19 are in proximity to the nose 5 and are provided with a series of circumferentially arranged teeth or spark points 21 which cooperate with the teeth of sparkpoints 6 in providing contiguous terminals between which sparks may jump for ignition purposes. Of the multiplicity of spark points there will always be a plurality of such points in condition for sparking purposes, consequently there will be a multiplicity of sparks and a positive operation 01" the spark plug insured when in an ignition system.

The upper or outer end of the electrode rod 16 terminates in a resistance head 22 set in the upper or outer end of the insulator 10 in spaced relation to another head 23 extending into the insulator and carried by a terminal 24 to which a Wire may be connected. The terminal 24 extends through a protecting cap 25 on the upper or outer end of the insulator 10 and when the usual wire clamping nut is screwed on the terminal, the head 23 may be clamped against the inner face of the cap 25 and held in spaced relation to the resistance head 22. With a gap between the heads 22 and 23 there will be a resistance in the ignition circuit which will render a magneto more active, at low speed, as a source of electrical energy for the ignition system of an automobile, the said heads 22 and 23 having upwardly and downwardly extending annular rims respectively, ensuring extensive sparking edges within the insulator.

As illustrated in Fig. 5, the rod 16 may have an integral electrode 26,but in practice it is preferable to make the electrode and its supporting rod of two parts, so that various types of electrodes may be used; examples of which are shown in Figs. 2, 3 and at.

In Fig. 2 the nose 5 of the spark plug body is partially closed by an inturned flange 27 provided with an annular head 28 confronting a similar bead 2.9 on an electrode 30.. The heads 28 and 29 provide a spark gap and with the nose almost closed and protected by the electrode 30 there is little likelihood of foreign matter entering the spark plug body or packing about the electrodes thereof.

28 As in Fig. 3 a detachable electrode 31 may have a plurality of teats .or bosses 32, and as shown in Fig. 4, an electrode 33 may have a bead 34L terminating in a knife edge 35.

It is thought that the utility of my spark plug will be apparent without further description, and while in the drawinp there are illustrated the preferred embodiments of my invention, it is to be understood that the structural elements are susceptible to such changes as fall within the scope of the appended claim.

That I claim is In a spark plug, an insulator, an electrode rod axially of said insulator, a resistance head having an upwardly extending annular rim on the outer end of said electrode rod and set in said insulator, a cap on said insulator, a terminal in said cap, and a resistance head having a downwardly extending annular rim in said insulator opposed to the first mentioned head and retained against said cap by said terminal.

In testimony whereof I aflix my signature.

GEORGE HADRICI-L 

